1. Field of the Invention
The present invention relates to an information processing apparatus and method for retrieving desired information from the stored information. More particularly, the present invention relates to an information processing apparatus and method suitable for retrieving desired information from information including image data, audio data, character data (e.g., fonts).
2. Related Background Art
A general information retrieval apparatus will be described with reference to an example for retrieving data from an image database. FIG. 13 is a block diagram showing the arrangement of a conventional image retrieval system. In this information retrieval apparatus, after an image is input, it is compressed (132). A language keyword is applied to the compressed data for each image (133), and the resultant data is stored in the storage (134). By this processing, the image database is created.
In retrieving image data, a desired retrieval class is used as a keyword, and the keyword is input as retrieval input information to a keyword retrieval process circuit. The range of image data is narrowed by a language keyword applied to each image in accordance with this retrieval input information (130). A group of image data (i.e., a group of compressed data) selected within a range limited to some extent in accordance with keyword retrieval are sequentially expanded and reproduced (131). Desired data is finally confirmed with visual observation.
For such an application purpose, a technique using progressive coding in the image compression process is available. In the reproduction mode, a progressive decoding process sequentially progresses from an image having a low resolution to an image having a high resolution. The currently displayed image can be switched to the next image when the user decides that the currently displayed image is not required. This technique is often used because a wasteful retrieval time can be eliminated.
The above image retrieval system has the following two problems.
(1) In either image retrieval technique, each image must be expanded during retrieval.
(2) In either image retrieval technique, visual confirmation is required except for a case using a language keyword.
These two problems become more conspicuous when a future database has a larger capacity, and access is made to a remote database.
Along with an advance in future networking, a user often has an opportunity to access distributed databases, thereby retrieving information. Image data must be transferred through a network due to the above problems. The large volume of data must be transferred through the network although the data are compressed.